Binder-free Cu-Sb-Sn-Zn-P alloys as high-efficiency anodes for sodium-ion batteries via double-pulse electrodeposition

Alloy anodes are widely recognized for their high theoretical specific capacity and have garnered significant attention among the anode materials studied for sodium-ion batteries. In this study, we synthesize Cu68.6Sb23.0Sn3.2Zn0.3P4.9 anodes using a double-pulse electrodeposition method. This binder-free alloy anode, comprising five high-capacity elements, significantly enhances specific capacity and improves cycling stability, while also demonstrating excellent sodium storage capability. Specifically, the Cu68.6Sb23.0Sn3.2Zn0.3P4.9 anode achieves an initial charge capacity of 368.8 mAh∙g−1 and remains highly stable over 100 cycles, with a capacity decay of only 0.1 %. In addition, the anode delivers 290.3 mAh∙g−1 even at a current density of 3200 mA∙g−1. The outstanding electrochemical performance can be attributed to improved electronic transfer efficiency due to the introduction of Cu into Cu68.6Sb23.0Sn3.2Zn0.3P4.9 alloy via reverse potential, as well as the porous structure that facilitates electrolyte penetration and sodium ion transport. The galvanostatic intermittent titration technique reveals a high sodium ion diffusion coefficient, further highlighting the potential of this alloy anode in advancing sodium-ion batteries. [Display omitted] •Double-pulse electrodeposition is a novel method to prepare alloy anode materials to improve sodium storage performance.•Introducing reverse voltage deposition of copper enhances the electronic conductivity of the alloy and accelerates charge delocalization.•Special Porous structure facilitates electrolyte permeation and sodium ion transport to improve electrochemical performance.